GHSA-J7PX-6HWJ-HPJG
Vulnerability from github – Published: 2021-12-20 17:59 – Updated: 2024-02-15 06:33
VLAI?
Summary
Open Redirect in OAuth2 Proxy
Details
Impact
As users can provide a redirect address for the proxy to send the authenticated user to at the end of the authentication flow. This is expected to be the original URL that the user was trying to access. This redirect URL is checked within the proxy and validated before redirecting the user to prevent malicious actors providing redirects to potentially harmful sites.
However, by crafting a redirect URL with HTML encoded whitespace characters (eg. %0a, %0b,%09,%0d) the validation could be bypassed and allow a redirect to any URL provided.
Patches
@rootxharsh and @iamnoooob provided this patch as potential solution:
From 4b941f56eda310b5c4dc8080b7635a6bfabccad4 Mon Sep 17 00:00:00 2001
From: Harsh Jaiswal <harsh@pop-os.localdomain>
Date: Fri, 1 May 2020 20:38:31 +0530
Subject: [PATCH] Fixes redirect issue
---
oauthproxy.go | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/oauthproxy.go b/oauthproxy.go
index 1e9bb7c..f8beb4d 100644
--- a/oauthproxy.go
+++ b/oauthproxy.go
@@ -577,8 +577,9 @@ func validOptionalPort(port string) bool {
// IsValidRedirect checks whether the redirect URL is whitelisted
func (p *OAuthProxy) IsValidRedirect(redirect string) bool {
+ matched, _ := regexp.MatchString(`^/\s+/|\\`, redirect)
switch {
- case strings.HasPrefix(redirect, "/") && !strings.HasPrefix(redirect, "//") && !strings.HasPrefix(redirect, "/\\"):
+ case strings.HasPrefix(redirect, "/") && !strings.HasPrefix(redirect, "//") && !matched:
return true
case strings.HasPrefix(redirect, "http://") || strings.HasPrefix(redirect, "https://"):
redirectURL, err := url.Parse(redirect)
--
2.17.1
This issue was also reported to us separately by @mik317 several hours later
The fix was implemented in #xxx and released as version 5.1.1
Severity ?
7.1 (High)
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/oauth2-proxy/oauth2-proxy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "5.1.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2020-11053"
],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": true,
"github_reviewed_at": "2021-05-24T21:05:58Z",
"nvd_published_at": "2020-05-07T21:15:11Z",
"severity": "HIGH"
},
"details": "### Impact\nAs users can provide a redirect address for the proxy to send the authenticated user to at the end of the authentication flow. This is expected to be the original URL that the user was trying to access.\nThis redirect URL is checked within the proxy and validated before redirecting the user to prevent malicious actors providing redirects to potentially harmful sites.\n\nHowever, by crafting a redirect URL with HTML encoded whitespace characters (eg. `%0a`, `%0b`,`%09`,`%0d`) the validation could be bypassed and allow a redirect to any URL provided.\n\n### Patches\n@rootxharsh and @iamnoooob provided this patch as potential solution:\n```\nFrom 4b941f56eda310b5c4dc8080b7635a6bfabccad4 Mon Sep 17 00:00:00 2001\nFrom: Harsh Jaiswal \u003charsh@pop-os.localdomain\u003e\nDate: Fri, 1 May 2020 20:38:31 +0530\nSubject: [PATCH] Fixes redirect issue\n\n---\n oauthproxy.go | 3 ++-\n 1 file changed, 2 insertions(+), 1 deletion(-)\n\ndiff --git a/oauthproxy.go b/oauthproxy.go\nindex 1e9bb7c..f8beb4d 100644\n--- a/oauthproxy.go\n+++ b/oauthproxy.go\n@@ -577,8 +577,9 @@ func validOptionalPort(port string) bool {\n\n // IsValidRedirect checks whether the redirect URL is whitelisted\n func (p *OAuthProxy) IsValidRedirect(redirect string) bool {\n+ matched, _ := regexp.MatchString(`^/\\s+/|\\\\`, redirect)\n switch {\n- case strings.HasPrefix(redirect, \"/\") \u0026\u0026 !strings.HasPrefix(redirect, \"//\") \u0026\u0026 !strings.HasPrefix(redirect, \"/\\\\\"):\n+ case strings.HasPrefix(redirect, \"/\") \u0026\u0026 !strings.HasPrefix(redirect, \"//\") \u0026\u0026 !matched:\n return true\n case strings.HasPrefix(redirect, \"http://\") || strings.HasPrefix(redirect, \"https://\"):\n redirectURL, err := url.Parse(redirect)\n--\n2.17.1\n```\n\nThis issue was also reported to us separately by @mik317 several hours later\n\nThe fix was implemented in [#xxx]() and released as version 5.1.1",
"id": "GHSA-j7px-6hwj-hpjg",
"modified": "2024-02-15T06:33:23Z",
"published": "2021-12-20T17:59:10Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-j7px-6hwj-hpjg"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2020-11053"
},
{
"type": "WEB",
"url": "https://github.com/oauth2-proxy/oauth2-proxy/commit/0d5fa211df8ef2449347a56b22c779eb8d894c43"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L",
"type": "CVSS_V3"
}
],
"summary": "Open Redirect in OAuth2 Proxy"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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